Do you have power to your slide? It sounds to me like your converter gave up the ghost on the DC side. That would cause it to stop charging your battery (probably) and your 12V (lights, CO detector, fridge controls) would be running straight off your battery. With nothing charging it, it wouldn't last long. Once it died, the CO detector would generally start to beep a low voltage warning and lights and fridge would stop working.

When you say you checked your fuses... does that include the 40amp fuses in your converter? Not sure how many you have in your camper, but I have two in my Flagstaff TT. How do I know that? Don't ask....

Your converter is not charging your battery.
You require 12 VDC to run the fridge even if 120 volt AC is available.

So:

1) Check and reset all the AC circuit breakers - one of them powers the converter/charger. Turn them OFF; then back on. A tripped AC breaker may look "good" Mine is labeled CONV in the photo

2) check the two orange 40 amp reverse current protection fuses in the DC distribution panel

3) check the two current limiters between the converter and the battery. They look like the photo and one is located VERY close to the battery box and the other is located at the steel pancake box that the tow vehicle umbilical cable goes into. See photos

The reset buttons are on the side.

Make SURE the current limiters do not look like the bad ones in the photo.